Precision measurement of $ u_{\mu}$ disappearance by T2K.
Erez Reinherz-Aronis · DESY (CERN, DESY, Fermilab, IHEP, and SLAC) · 2014
T2K is a long-baseline neutrino oscillation experiment, where a muon neutrino beam is produced at the J-PARC facility and after traveling 295 km it is detected by Super-Kamiokande, a water Cherenkov detector with a 22.5 kton fiducial mass.One aim of the experiment is to precisely determine the mixing angle $\theta_{23}$ and the mass squared difference $\Delta m^2_{23}$ using a measurement of muon neutrino disappearance. The T2K accumulated dataset is $6.57\times 10^{20}$ protons on target, which is 8\% of the experimental goal. Here we present an analysis of the T2K muon neutrino disappearance data and the world’s best constraint on the value of the mixing angle $\theta_{23}$ obtained by this analysis.